Infusion set

ABSTRACT

A infusion set which comprises a base (11) which is adapted to be capable of being manipulated by a user to effect insertion or removal of the infusion set and supporting a hollow needle (12) where the hollow needle has a pointed free end (18) and the other end of the hollow needle is supported from the base, a flexible delivery tube having one end connected to the other end of the needle and a portion at a position spaced from its one end being supported from a housing (14) and where a flexible duct (23) is concentrically provided over the flexible tubing (13) between the base (11). The flexible tubing being capable of slidable movement within the duct to cause slidable movement of the needle (12) in the base (11). The housing (14) has an engagement means (27) movable on the housing (14) and in engagement with the flexible tubing (13) to cause the slidable movement of the needle (12) in the base (11) between an extended position and a retracted position on movement of the engagement means.

THIS INVENTION relates to an infusion set.

Throughout the specification she term "infusion set" shall be taken ascomprising a base adapted to be capable of being manipulated by a userto effect insertion or removal of the infusion set, a hollow needlehaving one pointed free end and the other end supported from the baseand a flexible delivery tube connected at one end to the other end ofthe needle, the other end of the flexible delivery tube being adapted tobe connected to a receptacle or delivery means.

Infusion sets of the type described above are associated with a veryhigh incidence of accidental needle stick injury. One reason for such isbecause in use, after the user has removed the line from the vein of apatient the needle is usually held such that it is suspended from theflexible delivery tubing and is therefore able to move in aunpredictable manner due to the flexible resilient nature of theflexible delivery tubing. Also the needle can be difficult to controlwhen suspended from the flexible delivery tubing when being carried to asafe "sharps" disposal container and then can be difficult to insert into the "sharps" container without the risk of puncturing the hands orarms of the user. There is also significant danger to any persons in thevicinity of the user when the used infusion set is being carried.Furthermore, such infusion sets carry a high risk of transmission ofinfection such as HIV, Hepatitis and the like ailments due to thesubstantial quantity of blood remaining within the infusion set.

It is an object of this invention to provide an infusion set which oncompletion of its use can be rendered safe.

In one form the invention resides in an infusion set where a portion ofthe flexible delivery tube is supported at a position spaced from itsone end from a housing and where a flexible duct is concentricallyprovided over the flexible tubing between the base and the housing toenable slidable movement of the flexible tubing within the duct, saidneedle being longitudinally slidable in the base, said housing having anengagement means movable on the housing and in engagement with theflexible tubing to cause longitudinal movement of the needle in the basebetween an extended position and retracted position on movement of theengagement means.

According to a preferred feature of the invention, a delivery tube issubstantially inextendable.

According to a further preferred feature of the invention, the needle issubstantially incapable of rotation about its central axis with respectof the base. This can be achieved in one embodiment by forming theportion of the needle accommodated within the base when in the extendedposition to be asymmetric about its central axis and a passage formed inthe base of a complementary cross-sectional configuration. One form ofasymmetry comprises forming the needle to be convoluted. Alternatively,the needle may be supported within the base by a hub which is slidablyreceived in the base and if desired the hub may be configured such thatit is incapable of rotation within the passage. This latter function canbe achieved by forming the hub to be non circular and the passage ofcomplementary configuration.

According to a preferred feature of the invention, the needle when inthe retracted position is engaged with the base to prevent movement fromthe retracted position to the extended position. In addition, the needleis preferably engagable with the base when at the extended position toprevent movement from the extended position until after a predeterminedforce has been applied to the needle by the delivery tube. The retentionof the needle in the extended position and the retracted position may beprovided by a first detent means and a second detent means respectivelyin the base which is engagable by the needle and/or the hub supportingthe needle when at the extended or retracted position respectively.

According to a further preferred feature of the invention, theengagement means is incapable of a movement with respect to the housingwhich would enable longitudinal movement of the needle from theretracted position to the extended position. In addition, theaccommodation of the delivery tube within the housing is such as toprevent movement of the delivery tube from the housing into the flexibleduct. In addition, the engagement means may take the form of a sliderslidably supported on the housing or alternatively a capstan-likeelement rotatably supported on the housing.

The invention will be more fully understood in the light of thefollowing description of one specific embodiment. The description ismade with reference to the accompanying drawings of which;

FIG. 1 is an isometric view of an infusion set according to theembodiment;

FIG. 2 is an upper plan view of the housing of the embodiment;

FIG. 3 is a sectional plan view of the housing according to theembodiment;

FIG. 4 is a sectional side elevation of the housing according to theembodiment;

FIG. 5 is a sectional plan view of the base and needle according to theembodiment;

FIG. 6 is a sectional side elevation of the base and needle according tothe embodiment; and

FIG. 7 is a sectional end elevation of the base and needle according tothe embodiment.

The infusion set according to the embodiment comprises a base 11, aneedle 12, a flexible delivery tube 13 received within a flexible duct23 and a housing 14.

The base 11 comprises a central tubular member 15 with a pair of lateralwing members 16 mounted thereto in diametrically opposed relation. Thejunction between the wing members 16 and the tubular portion 15 areprovided with a reduced thickness portion to provide a hinged connection17 between the wings 16 and the tubular portion 15. In use, the wings 16occupy the position as shown at which they extend to opposite sides ofthe tubular portion 15. When in that position they can be fixed to thearm or body of patient by use of suitable tape. When it becomesnecessary to insert the infusion set, the wings 16 are hinged to aposition (not shown) at which they are substantially adjacent andparallel to each other whereby they can be grasped between a thumb and afinger of the user to enable insertion.

The needle 12 is hollow and has one end 18 which is free and formed to asharp point, while the other end 19 (see FIG. 6) is connected to one end20 of the flexible delivery tube 13, whereby the interior of the hollowneedle 12 is in open communication with the interior of the flexibledelivery tube 13. The needle 12 is slidably supported within the tubularmember 15. The flexible delivery tube 13 is received within the body ofthe housing 14 such that it enters the interior of the housing 14 at theproximate end of the housing 14 most adjacent the base 11 and is fixedat its other end 21 to the remote end of the housing 14 which is mostremote from the base 11. The flexible delivery tube is substantiallyinextensible. This may be effected by choice of the appropriate materialor associating it with a fine wire bonded or fixed to the tube and fixedat one end to the tubular portion 13 and at the other end to the housing14.

The remote end of the housing 14 is provided with a socket 22 which isshaped to sealingly receive the "LUER" fitting of a conventional syringeor receptacle used in relation to such infusion set and the other end 21of the flexible delivery tube is fixed to the socket 22. Alternatively,the socket may be configured to sealingly receive any other conventionalfitting which may be able to be used. Such a fitting may comprise a portor similar plug which can be pierced by a syringe or like means tosealingly deliver an agent to the delivery tube 13.

The base 15 is supported from the proximate end of the housing 14 by aflexible tubular duct 23 which is concentrically received over theflexible delivery tube 13 and is fixed at one end to the base 15 and atthe other end to a tubular boss 24 provided at the proximate end of thehousing. The flexible tubular duct 23 may take any suitable form andneed not be sealed. If desired it may incorporate or comprise a closelywound wire coil.

The interior of the housing 14 is provided with a pair of parallelguides 25 spaced to each side of the central axis between the proximateand remote end of the housing 14 and the wall of the upper face of thehousing is formed with a longitudinal slot 26 which is locatedintermediate of the ribs 25. The ribs support between themselves theengagement means which takes the form of a slider 27 which is slidablyreceived between the ribs 25 for longitudinal movement within thehousing 14 and which is associated with a control knob or handle 28which is received within the slot 26 whereby the knob may be manipulatedto cause slidable movement of the slider 27 within the housing 14.

The slider 27 is provided with a circular boss 29 which is associatedwith a concentric part circular arcuate rib 30 at the side of the bossremote from the proximate end of the housing 14 to define channel shapedspace between the boss 29 and the arcuate rib 30 which is able toslidably receive the flexible delivery tube 13.

The housing is further provided with a set of guide ribs 31 adjacent oneexterior face of one of the longitudinal ribs 25. The guide ribs serveto define a convoluted pathway which is an extension of that definedbetween the boss 29 and the arcuate rib 30 on the slider 27.

The portion of the flexible delivery tube 13 which is accommodatedwithin the housing 14 is received in the convoluted pathway definedbetween the boss 29 and arcuate rib 30 on the slider 27 and the guideribs 31 provided in the housing. The pathway is such that when theslider 27 is at its first position adjacent the proximate end of thehousing 14 the pathway defined for the flexible tubing is arcuatewhereby no kinks are induced in the flexible delivery tubing 13.

The engagement between the slider 27 and the flexible tubing 13 is suchthat on the slider 27 being moved longitudinally within the housing awayfrom the proximate end thereof to its second position adjacent theremote end, a portion of flexible delivery tubing 13 accommodated withinthe duct 23 is drawn into the interior of the housing 14 whichconsequently causes the movement of the needle 12 into the tubularportion 15 of the base 11. When the slider is at its second positionmost adjacent the remote end of the housing 14 the flexible deliverytube 13 has been sufficiently drawn into the body of the housing 14 toenable full retraction of the needle 12 into the tubular portion 15 andsuch that the free end 18 of the needle is unexposed. The flexiblenature of the flexile delivery tube 13 is such that on the slider 27being moved from its second position most adjacent the remote end of thehousing 14 to its first position most adjacent the proximate end of thehousing 14 the portion of the flexible tubing within the housing 14 isnot caused to re-enter the delivery duct 23 but will be caused to flex.

The mounting of the needle 12 within the tubular portion 15 is such thatthe needle is incapable of relative rotational movement within thetubular portion 15. In the case of the embodiment this is effected byforming the inner portion of the needle 12 with a series of convolutionswhich are substantially coplanar. The passageway in the tubular portion15 is formed at its end adjacent the housing with an expanded portion ofoval cross section which is shaped to be able to receive the convolutedportion of the needle 12. The interengagement of the convolutions 32within the expanded portion 33 of the passageway within the tubularportion 15 serves to prevent relative rotation of the needle 12 withrespect to the base 11. Furthermore, on retraction of the needle 12 intothe tubular portion 15 of the base 11 as a result of the flexibledelivery tube 13 being drawn into the housing 14, the convolutions aredrawn into the duct 23 and become frictionally engaged with the innerwall of the duct 23. Such frictional engagement serves to resist anytendency that the flexible delivery tube may have to re-enter the duct23 from the housing 14 on movement of the slider 27 from its secondposition to its first position.

In order to retain the needle 12 in the extended position a detent suchas a dimple 34 in the interior of the expanded portion 33 of thepassageway in the tubular portion 15, engages a convolution when theneedle 12 is in the extended position. The dimple 34 provides sufficientresistance for the needle to be inserted into the body of a patient butsuch resistance can be overcome by the retractable movement of theslider 27.

If desired the slider 27 may be associated with a locking means whichwill ensure locking engagement between the slider 27 and the body of thehousing 14 on the slider 27 being moved to its retracted position.Furthermore, the housing 14 may be associated with suitable stops ordetent means (not shown) which will provide a tactile indication to theuser on movement of the control knob 28 to indicate that the knob hasbeen moved to either of its end positions.

In another embodiment the base may be formed such that on manipulationof the wings 16 the passage accommodating the needle is changed incross-sectional configuration whereby when the wings are in theirnatural unstressed state the needle is held in position and when thewings are folded in a particular manner the needle is able to move inthe passage. In such an arrangement the needle is also retained inposition when the wings have been folded to a position enabling the baseto be held by an operator by the folded wings and the needle insertedinto the body of the patient.

The means for retracting the needle need not have the form as describedin relation to the embodiment but may comprise any means of causingretraction of the flexible delivery tube into the body of the housing 14to effect retraction of the needle 12.

In an alternative embodiment the engagement means may comprise a capstanor a like element which is rotatably supported on or in the housing andwhich is able to wind the flexible delivery tube into the housing. Ifdesired, the capstan is only rotatable on the housing in one directionin order to enable a retractable movement of the needle only.

In addition, in both embodiments the movement of the engaging means tothe retracted position may cause a destructive bending or "kinking" ofthe delivery tube to render the infusion set incapable of further use.In the case of the embodiment described above in relation to thedrawings the arrangement of the slider with respect to the base is suchthat in the event of inadvertent movement of the slider from theretracted position to the extended position the delivery tube folds upor "kinks" rather than causing movement of the needle to the extendedposition.

Furthermore the configuration applied to the needle to ensure that it isnot capable of rotation within the base may taken any desirable form.

In a further embodiment the needle is unconvoluted and is provided witha hub member which is slidably received in the tubular member. The hubis associated with a first detent to retain the needle in the extendedposition during use from which it can be released with appropriate forcebeing applied to the delivery tube. The hub may be associated with asecond detent or similar engagement means which engages and retains thehub and needle in the retracted position.

In another embodiment the first detent may comprise a protrusion in thepassage towards the outer end which is positioned and shaped to beengaged by the free end of the needle when the needle is moved to theretracted position. The arrangement is such that on the needle beingmoved to the retracted position the free end moves past the protrusionand if an attempt is made to move the needle to the extended positionthe free end engages the protrusion to prevent further movement of theneedle out of the passage.

It should be appreciated that the scope of the invention should not belimited to the particular scope of the above embodiment.

THE CLAIMS defining the invention are as follows;

I claim:
 1. An infusion set comprising:a portion of a flexible deliverytube which is supported at a position spaced from one end of the tubefrom a housing; a flexible duct which is concentrically provided overthe flexible delivery tube between a base and the housing to enableslidable movement of the flexible delivery tube within the duct; andneedle being received in the one end of the flexible delivery tube, theneedle further being longitudinally slidable in the base, said housinghaving an engagement means movable on the housing for engaging theflexible delivery tube to cause longitudinal movement of the needle inthe base between an extended position and a retracted position onmovement of the engagement means.
 2. An infusion set as claimed in claim1 wherein the delivery tube is not extendible.
 3. An infusion set asclaimed in claim 1 wherein the needle is not rotatable about a centralaxis of the needle with respect to the base.
 4. An infusion set asclaimed in claim 1 wherein said needle is engaged with the base whenmoved from the extended position to the retracted position to preventmovement to the extended position from the retracted position.
 5. Aninfusion set as claimed in claim 4 wherein the needle is engaged withthe base to prevent movement from the extended position until after apredetermined force has been applied to the needle by the delivery tube.6. An infusion set as claimed in claim 5 wherein the base is providedwith a first detent means which is engagable by the needle when in theextended position to prevent said movement from the extended position.7. An infusion set as claimed in claim 4 wherein the base is providedwith a second detent means which is engaged by the needle when in theretracted position to prevent said movement from the retracted position.8. An infusion set as claimed in claim 7 wherein at least a portion ofthe needle accommodated within the base when in the extended position isasymmetric about a central axis of the needle and is received in apassage formed in the base of complementary cross-sectionalconfiguration.
 9. An infusion set as claimed in claim 7 wherein aportion of the needle accommodated within the base is supported by a hubmember slidably receivable in a passage formed in the base.
 10. Aninfusion set as claimed in claim 9 wherein the hub is engaged with thesecond detent means.
 11. An infusion set as claimed in claim 8 whereinthe portion of the needle is convoluted.
 12. An infusion set as claimedin claim 1 wherein the engagement means comprises a slider slidablysupported from the housing whereby slidable movement of a slider causessaid longitudinal movement of the needle.
 13. An infusion set as claimedin claim 12 wherein said engagement means comprises a capstan-likeelement rotatably supported in the housing whereby rotation of acapstan-like element causes said longitudinal movement of the needle.14. An infusion set as claimed in claim 1 wherein the engagement meansin its movement on the housing is not able to effect longitudinalmovement of the needle from the retracted position to the extendedposition.
 15. An infusion set as claimed in claim 1 whereinaccommodation of the delivery tube within the housing is such as toprevent movement of the delivery tube from the housing into the flexibleduct.
 16. An infusion set as claimed in claim 2 wherein the needle isnot rotatable about a central axis of the needle with respect to thebase.
 17. An infusion set as claimed in claim 2 wherein said needle isengaged with the base when moved from the extended position to theretracted position to prevent movement to the extended position from theretracted position.
 18. An infusion set as claimed in claim 3 whereinsaid needle is engaged with the base when moved from the extendedposition to the retracted position to prevent movement to the extendedposition from the retracted position.
 19. An infusion set as claimed inclaim 1 wherein the needle is engaged with the base to prevent movementfrom the extended position until after a predetermined force has beenapplied to the needle by the delivery tube.
 20. An infusion set asclaimed in claim 2 wherein the needle is engaged with the base toprevent movement from the extended position until after a predeterminedforce has been applied to the needle by the delivery tube.
 21. Aninfusion set as claimed in claim 5 wherein the base is provided with asecond detent means which is engaged by the needle when in the retractedposition to prevent said movement from the retracted position.
 22. Aninfusion set as claimed in claim 6 wherein the base is provided with asecond detent means which is engaged by the needle when in the retractedposition to prevent said movement from the retracted position.